Electric driving system of multi-rotor aircraft

Abstract

The utility model discloses an electric driving system of a multi-rotor aircraft, which comprises a motor and a two-stage compound planetary gear mechanism, and a motor shaft of the motor is connected with an input end of the two-stage compound planetary gear mechanism; the two-stage compound planetary gear mechanism is a coaxial speed reducer with a large reduction ratio, and the transmission output end of the speed reducer is connected with the rotor wing. The electric driving system is matched with each rotor wing in the aircraft in a one-to-one correspondence manner, the high-speed motor is adopted, the matched speed reducing mechanism is compact in structure, belongs to a two-stage compound planetary gear mechanism, reduces first-stage energy loss, is high in transmission efficiency, is coaxially arranged with the motor, and is regular in appearance and easy to arrange.

Description

TECHNICAL FIELD

[0001] The utility model discloses a kind of multi-rotor aircraft electric drive systems, belong to unmanned aerial vehicle technical field, specifically related to a kind of multi-rotor aircraft. BACKGROUND

[0002] Now multi-rotor aircraft is developing rapidly, has a wide market, and is growing rapidly. Multi-rotor aircraft includes but is not limited to: various rotor unmanned aerial vehicles, manned rotor aircraft, flying cars, etc. There are a large number of small rotor unmanned aerial vehicles on the market, with a load of several kilograms to several dozen kilograms, and a small rotor diameter; the motor speed driving the rotor is not very high, several thousand revolutions per second, which can be directly driven. Larger multi-rotor aircraft, with a load of several hundred kilograms or even several tons, several dozen tons, rely entirely on rotor lift, so they need larger rotors. The rotor needs to be powered, and single-rotor or dual-rotor aircraft use engines to drive, with one engine driving one rotor. For aircraft with more than three rotors, engine drive is not practical, and is often electrically driven. The most commonly used multi-rotor aircraft is electrically driven rotors, that is, each rotor is matched with a set of electric drive system. Heavy rotor aircraft requires large lift, which requires large rotors. The rotor's ability to provide lift is directly proportional to the square of the rotor length; however, the speed of large rotors cannot be too high, otherwise the rotor efficiency will be reduced. For low-speed large rotors, if the motor is still used to directly drive the rotor, or a small speed ratio reduction mechanism is used, only a low-speed drive motor can be matched, which requires a large torque output from the motor; a large torque motor will inevitably result in an increase in size and weight. The weight and internal space of the aircraft are crucial and must be reduced in every possible way to save weight and space, requiring high-power-density electric drive systems. Increasing motor speed can increase motor power density, because motor power is equal to motor torque multiplied by speed: with the same motor power, if the motor speed is high, the motor torque is small, and the weight and size are small. Previously, the motor speed was several thousand revolutions, more than ten thousand revolutions, and in the future, the motor speed can reach 20,000 rpm, and even possibly 25,000-30,000 rpm. This creates a contradiction: the speed of the drive motor is above 20,000 rpm, but the speed of the matched rotor is in the range of a few hundred rpm to more than a thousand rpm, with a difference of several dozen times. A reduction mechanism is needed to reduce the high-speed power output by the motor and increase the torque to match the requirements of the rotor. The motor and rotor speeds differ by several dozen times, requiring a reduction mechanism of several dozen times. For example, a 30:1 reduction mechanism, ordinary parallel shaft gear reduction mechanism requires three-stage reduction, and a series planetary gear reduction mechanism requires three-stage planetary gear. Because whether it is a parallel shaft gear or a planetary gear mechanism, the single-stage reduction ratio is generally less than 5:1, so to achieve a speed ratio of 30:1, three-stage reduction is required. Such a reduction mechanism is not ideal: each stage of mechanical transmission will result in loss, three-stage reduction results in three times energy loss, increasing the energy loss of the aircraft; three-stage reduction gears have large size and weight, which is not conducive to weight reduction of the aircraft; parallel shaft gear reduction mechanism is a non-coaxial reduction mechanism, with a complex L-shaped shape and a much larger space than volume; three-stage planetary gear mechanism has a complex structure, including three sets of sun gears, three sets of planetary gears, three sets of planet carriers, and three sets of ring gears, as well as many small shafts and bearings, and connecting parts, etc. SUMMARY

[0003] In order to overcome the defects of the prior art, the utility model provides a kind of multi-rotor aircraft electric drive system, adopt high-speed motor, match the coaxial reduction mechanism of big reduction ratio, with transmission efficiency is high, light in weight, layout is convenient and so on Advantage.

[0004] To achieve the above object, the utility model is realized by the following technical scheme:

[0005] A kind of multi-rotor aircraft electric drive system, including motor and two-stage compound planetary gear mechanism, motor has motor shaft, the motor shaft is connected with the input end of two-stage compound planetary gear mechanism;

[0006] Two-stage compound planetary gear mechanism, it is the coaxial reducer of big reduction ratio, the transmission output end of this reducer is connected with rotor.

[0007] Further, motor is high-power density motor, the motor and two-stage compound planetary gear mechanism are coaxially arranged in shell, two-stage compound planetary gear mechanism has output shaft, the output shaft is assembled on shell to form transmission output end, and is connected with rotor.

[0008] Further, the electric drive system is matched with each rotor in aircraft one to one, motor is high-speed motor, rotation speed 20000rpm above.

[0009] Further, the reduction ratio range of two-stage compound planetary gear mechanism is: 15:1~60:1.

[0010] Further, two-stage compound planetary gear mechanism includes sun gear, first planetary gear, planet carrier, support gear, second planetary gear, output gear;

[0011] First planetary gear and second planetary gear are coaxially fixedly connected, rotate around its own shaft, and the effective radius or tooth number of first planetary gear and second planetary gear is different;

[0012] The shaft of first planetary gear and second planetary gear is assembled on planet carrier, the axis of sun gear and the axis of planet carrier coincide;

[0013] Sun gear is engaged with first planetary gear or second planetary gear, first planetary gear is engaged with support gear, first planetary gear drives second planetary gear to rotate, second planetary gear is engaged with output gear, and output gear is connected with output shaft for output torque, and the output end of output shaft is connected with rotor.

[0014] Further, two-stage compound planetary gear mechanism includes first-stage planetary gear mechanism and second-stage planetary gear mechanism, first-stage planetary gear mechanism and second-stage planetary gear mechanism share planet carrier;

[0015] The first-stage planetary gear mechanism comprises a sun gear, a first planetary gear, a planet carrier, a support gear ring,

[0016] The second-stage planetary gear mechanism comprises a second planetary gear, a planet carrier, an output gear ring;

[0017] The sun gear drives the first planetary gear to move in a plane, the first planetary gear is coaxially fixedly connected with the second planetary gear, the second planetary gear moves in a plane along with the first planetary gear, so that the first planetary gear and the second planetary gear can rotate around the axis thereof and can revolve around the axis of the planet carrier, and the planet carrier can rotate around the axis thereof, the first planetary gear is engaged with the support gear ring, the second planetary gear is engaged with the output gear ring, and the output shaft of the output gear ring is connected with the rotor;

[0018] The rotation speed ratio of the sun gear to the output gear ring is:

[0019] Wherein, the number of teeth or effective radius of the sun gear is represented by S, the number of teeth or effective radius of the planetary gear is represented by P1, the number of teeth or effective radius of the planetary gear is represented by P2, the number of teeth or effective radius of the support gear ring is represented by R1, and the number of teeth or effective radius of the output gear ring is represented by R2.

[0020] Further, in the second-stage compound planetary gear mechanism, if the sun gear is engaged with the second planetary gear and other conditions remain unchanged, the rotation speed ratio of the sun gear or the motor shaft to the output gear ring is:

[0021]

[0022] Wherein, the number of teeth of the sun gear is represented by S, the number of teeth of the planetary gear is represented by P1, the number of teeth of the planetary gear is represented by P2, the number of teeth of the support gear ring is represented by R1, and the number of teeth of the output gear ring is represented by R2.

[0023] The utility model has the advantages of:

[0024] 1) The electric rotor system can be used in a battery-driven rotor aircraft, and can also be used in a rotor aircraft in which a motor drives a generator to generate electricity and drives a rotor motor to drive a rotor;

[0025] 2) One motor drives one rotor, which is flexible in arrangement, avoids complex mechanical transmission mechanisms, and is easy to control flight;

[0026] 3) The coaxial speed reduction mechanism in the system is compact in structure, regular in shape, such as cylindrical or other regular shapes, has reduced space occupation, and is easy to install and arrange;

[0027] 4) This system is a composite planetary gear system. Through planetary gear transmission, there are 3 to 5 gear meshing points, and the gear load is only one-third of that of the parallel shaft gear.

[0028] 5) This system is a two-stage compound planetary gear mechanism with fewer parts, lighter weight, smaller size, and higher efficiency, while other reduction mechanisms require three-stage reduction. Therefore, it has obvious comparative advantages in terms of weight, size, and efficiency.

[0029] 6) The high-speed motor used in this system has high power density, and when matched with a coaxial reduction mechanism with a large speed ratio, compact structure and light weight, the high power density advantage of the system is very prominent. Attached Figure Description

[0030] Figure 1 This is a cross-sectional view of an embodiment of the present invention.

[0031] Figure 2 This is a schematic diagram of an embodiment of the present invention.

[0032] Figure 3 This is a schematic diagram of another embodiment of the present invention.

[0033] Illustration markings:

[0034] 1. Shell

[0035] 2. Motor cable

[0036] 3. Motor stator

[0037] 4. Motor rotor

[0038] 5. Rotor shaft

[0039] 6. Rotor bearing

[0040] 7. Sun Gear S

[0041] 8. First planetary gear P1

[0042] 9. Planetary Carrier C

[0043] 10. Support gear ring R1

[0044] 11. Second planetary gear P2

[0045] 12. Output gear ring R2

[0046] 13. Output shaft

[0047] 14. Output bearing

[0048] 15. Rotor. Detailed Implementation

[0049] The utility model is further described below with reference to the drawings:

[0050] Embodiment: please refer to Figure 1 、 Figure 2 A multi-rotor aircraft electric drive system, comprising a motor and a two-stage compound planetary gear mechanism, the motor has a motor shaft, the motor shaft is connected with the input end of the two-stage compound planetary gear mechanism, the two-stage compound planetary gear mechanism is a coaxial reducer with a large speed reduction ratio, the transmission output end of the reducer is connected with the rotor.

[0051] The utility model discillator a multi-rotor aircraft electric drive system, also called as big speed ratio motor drive system, comprising a shell 1, motor power input interface 2 or motor cable external power supply, motor stator 3 and motor rotor 4, stator 3 is fixed on the shell 1 and relative to the shell 1 is not rotatable, rotor shaft 5 is assembled on the shell 1 through rotor bearing 6 and relative to the shell 1 is rotatable, and rotor shaft 5 extends outward to form a motor shaft.

[0052] The utility model discillator a multi-rotor aircraft electric drive system further includes two-stage compound planetary gear mechanism, which is a coaxial reducer or coaxial reduction mechanism, comprising sun gear 7, first planetary gear 8, planet carrier 9, support gear 10, second planetary gear 11 and output gear 12, first planetary gear 8 is coaxially fixedly connected with second planetary gear 11, rotates around its own shaft, and the effective radius or number of teeth of first planetary gear 8 and second planetary gear 11 is not the same, the shaft of first planetary gear 8 and second planetary gear 11 is assembled on planet carrier 9, the axis of sun gear 7 and the axis of planet carrier 9 are coincident, sun gear 7 is engaged with first planetary gear 8, first planetary gear 8 is engaged with support gear 10, first planetary gear 8 drives second planetary gear 11 to rotate, second planetary gear 11 is engaged with output gear 12, output gear 12 is connected with output shaft 13 for output torque, output shaft 13 is assembled on shell 1 through an output bearing 14 to form a transmission output end, and is connected with rotor 15.

[0053] The utility model discillator a two-stage compound planetary gear mechanism, as shown in Figure 2 The first-stage planetary gear mechanism comprises (first) sun gear 7, first planetary gear 8, planet carrier 9 and support gear 10, the second-stage planetary gear mechanism comprises second planetary gear 11, planet carrier 9 and output gear 12, and the second sun gear is omitted, and the first-stage and second-stage gear mechanisms share planet carrier 9.

[0054] When the sun gear 7 rotates, the first planetary gear 8 is driven to move in a plane, and the second planetary gear 11 is driven to move in a plane along with the first planetary gear 8, so that the first planetary gear 8 and the second planetary gear 11 can rotate around the axis thereof and can revolve around the axis of the planet carrier 9, and the planet carrier 9 can rotate around the axis thereof; at the same time, the second planetary gear 11 drives the output gear 12 to rotate through meshing teeth.

[0055] For the convenience of description, the number of teeth of the sun gear 7 is represented by S, the number of teeth of the first planetary gear 8 is represented by P1, the number of teeth of the second planetary gear 11 is represented by P2, the number of teeth of the supporting gear 10 is represented by R1, and the number of teeth of the output gear 12 is represented by R2. The speed ratio of the sun gear 7 to the output gear 12 is:

[0056]

[0057] Another embodiment structure of the two-stage compound planetary gear mechanism in the utility model is shown in the figure: Figure 3 The sun gear is meshed with the second planetary gear, and other structures are unchanged in cooperation relationship as shown in the figure: Figure 2

[0058] The number of teeth of the sun gear 7 is represented by S, the number of teeth of the planetary gear 8 is represented by P1, the number of teeth of the planetary gear 11 is represented by P2, the number of teeth of the gear 10 is represented by R1, and the number of teeth of the gear 12 is represented by R2. Then the speed ratio of the motor shaft 5 to the output shaft 13 is:

[0059] The utility model discloses a multi-rotor aircraft electric drive system is a high power density rotor electric drive system, first adopt high -speed motor, the speed 20000rpm above, has high power density, second, match the coaxial speed reduction mechanism of big reduction ratio, the reduction ratio range: 15: 1 ~ 60: 1, and the speed reduction mechanism is compact, small, light in weight, high in power density. The speed reduction mechanism belongs to two-stage compound planetary gear mechanism, reduces the energy loss of first stage, and the transmission efficiency is high, reduces the speed reduction mechanism of first stage, reduces many parts, reduces the cost, and the weight is light, and the appearance is regular, and it is easy to arrange, and the volume, the weight, the efficiency are dominant.

[0060] The above description is only an embodiment using the technical content of the present application, and any modification or change made by those skilled in the art using the present application is within the scope of the present application, and is not limited to the embodiments disclosed.​

Claims

1. A multi-copter electric drive system, characterized by: The motor has a motor shaft connected with an input end of the two-stage compound planetary gear mechanism; The two-stage compound planetary gear mechanism is a coaxial reducer with a large reduction ratio, and a transmission output end of the reducer is connected with the rotor.

2. The electric drive system for a multi-copter according to claim 1, wherein: The motor is a high-power-density motor, and the motor and the two-stage compound planetary gear mechanism are coaxially arranged in the shell. The two-stage compound planetary gear mechanism has an output shaft assembled on the shell to form the transmission output end and connected with the rotor.

3. The electric drive system of claim 1, wherein: The electric drive system is matched with each rotor in the aircraft one by one, the motor is a high-speed motor with a rotating speed of 20000 rpm or more.

4. The electric drive system of claim 1, wherein: The reduction ratio of the two-stage compound planetary gear mechanism ranges from 15:1 to 60:

1.

5. An electric drive system for a multi-copter aircraft according to one of claims 1 to 4, characterized in that: The two-stage compound planetary gear mechanism includes a sun gear, a first planetary gear, a planet carrier, a support ring, a second planetary gear and an output ring. The first planetary gear and the second planetary gear are coaxially fixedly connected, rotate around their own axes, and the effective radii or the number of teeth of the first planetary gear and the second planetary gear are different. The axes of the first planetary gear and the second planetary gear are assembled on the planet carrier, and the axis of the sun gear coincides with the axis of the planet carrier. The sun gear is meshed with the first planetary gear or the second planetary gear, the first planetary gear is meshed with the support ring, the first planetary gear drives the second planetary gear to rotate, the second planetary gear is meshed with the output ring, the output ring is connected with an output shaft for outputting torque, and the output end of the output shaft is connected with the rotor.

6. The electric drive system of claim 1, wherein: The two-stage compound planetary gear mechanism includes a first-stage planetary gear mechanism and a second-stage planetary gear mechanism, and the first-stage planetary gear mechanism and the second-stage planetary gear mechanism share the planet carrier. The first-stage planetary gear mechanism includes a sun gear, a first planetary gear, a planet carrier and a support ring. The second-stage planetary gear mechanism includes a second planetary gear, a planet carrier and an output ring. The sun gear directly drives the first planetary gear to do plane motion, the first planetary gear is coaxially fixedly connected with the second planetary gear, the second planetary gear follows the first planetary gear to do plane motion, so that the first planetary gear and the second planetary gear can rotate around their axes and revolve around the axis of the planet carrier, and the planet carrier can revolve around its axis, the first planetary gear is meshed with the support ring, the second planetary gear is meshed with the output ring, and the output shaft of the output ring is connected with the rotor.

7. The electric drive system of claim 6, wherein: The rotation speed ratio of the sun gear to the output ring gear is: Wherein the number of teeth or the effective radius of the sun gear is represented by S; the number of teeth or the effective radius of the first planetary gear is represented by P1; the number of teeth or the effective radius of the second planetary gear is represented by P2; the number of teeth or the effective radius of the support ring is represented by R1; and the number of teeth or the effective radius of the output ring is represented by R2.

8. The electric drive system of claim 6, wherein: The sun gear is meshed with the second planetary gear to drive the second planetary gear to do plane motion instead of directly driving the first planetary gear, and the first planetary gear follows the second planetary gear to do plane motion.

9. The electric drive system of claim 8, wherein: The rotational speed ratio of the sun gear or the motor shaft to the output ring gear is: Wherein the number of teeth of the sun gear is represented by S; the number of teeth of the first planetary gear is represented by P1; the number of teeth of the second planetary gear is represented by P2; the number of teeth of the support ring is represented by R1; and the number of teeth of the output ring is represented by R2.

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